1
|
Chen S, Sun Y, Qin Y, Yang L, Hao Z, Xu Z, Björklund M, Liu W, Hong Z. Dynamic interaction of REEP5-MFN1/2 enables mitochondrial hitchhiking on tubular ER. J Cell Biol 2024; 223:e202304031. [PMID: 39133213 DOI: 10.1083/jcb.202304031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 02/15/2024] [Accepted: 06/12/2024] [Indexed: 08/13/2024] Open
Abstract
Mitochondrial functions can be regulated by membrane contact sites with the endoplasmic reticulum (ER). These mitochondria-ER contact sites (MERCs) are functionally heterogeneous and maintained by various tethers. Here, we found that REEP5, an ER tubule-shaping protein, interacts with Mitofusins 1/2 to mediate mitochondrial distribution throughout the cytosol by a new transport mechanism, mitochondrial "hitchhiking" with tubular ER on microtubules. REEP5 depletion led to reduced tethering and increased perinuclear localization of mitochondria. Conversely, increasing REEP5 expression facilitated mitochondrial distribution throughout the cytoplasm. Rapamycin-induced irreversible REEP5-MFN1/2 interaction led to mitochondrial hyperfusion, implying that the dynamic release of mitochondria from tethering is necessary for normal mitochondrial distribution and dynamics. Functionally, disruption of MFN2-REEP5 interaction dynamics by forced dimerization or silencing REEP5 modulated the production of mitochondrial reactive oxygen species (ROS). Overall, our results indicate that dynamic REEP5-MFN1/2 interaction mediates cytosolic distribution and connectivity of the mitochondrial network by "hitchhiking" and this process regulates mitochondrial ROS, which is vital for multiple physiological functions.
Collapse
Affiliation(s)
- Shue Chen
- Department of Neurology, the Second Affiliated Hospital of Zhejiang University, School of Medicine, Zhejiang University, Hangzhou, China
- Centre for Cellular Biology and Signaling, Zhejiang University-University of Edinburgh Institute, Haining, China
- Nuclear Organization and Gene Expression Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Yang Sun
- Department of Neurology, the Second Affiliated Hospital of Zhejiang University, School of Medicine, Zhejiang University, Hangzhou, China
- Centre for Cellular Biology and Signaling, Zhejiang University-University of Edinburgh Institute, Haining, China
| | - Yuling Qin
- Department of Neurology, the Second Affiliated Hospital of Zhejiang University, School of Medicine, Zhejiang University, Hangzhou, China
- Centre for Cellular Biology and Signaling, Zhejiang University-University of Edinburgh Institute, Haining, China
| | - Lan Yang
- Department of Neurology, the Second Affiliated Hospital of Zhejiang University, School of Medicine, Zhejiang University, Hangzhou, China
- Centre for Cellular Biology and Signaling, Zhejiang University-University of Edinburgh Institute, Haining, China
| | - Zhenhua Hao
- National Center for Children's Health, Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Zhihao Xu
- Department of Neurology, the Second Affiliated Hospital of Zhejiang University, School of Medicine, Zhejiang University, Hangzhou, China
- Centre for Cellular Biology and Signaling, Zhejiang University-University of Edinburgh Institute, Haining, China
| | - Mikael Björklund
- Centre for Cellular Biology and Signaling, Zhejiang University-University of Edinburgh Institute, Haining, China
- University of Edinburgh Medical School, Biomedical Sciences, College of Medicine & Veterinary Medicine, University of Edinburgh, Edinburgh, UK
| | - Wei Liu
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, School of Medicine, Zhejiang University, Yiwu, China
| | - Zhi Hong
- Department of Neurology, the Second Affiliated Hospital of Zhejiang University, School of Medicine, Zhejiang University, Hangzhou, China
- Centre for Cellular Biology and Signaling, Zhejiang University-University of Edinburgh Institute, Haining, China
- University of Edinburgh Medical School, Biomedical Sciences, College of Medicine & Veterinary Medicine, University of Edinburgh, Edinburgh, UK
| |
Collapse
|
2
|
Sundaresan Y, Yacoub S, Kodati B, Amankwa CE, Raola A, Zode G. Therapeutic applications of CRISPR/Cas9 gene editing technology for the treatment of ocular diseases. FEBS J 2023; 290:5248-5269. [PMID: 36877952 PMCID: PMC10480348 DOI: 10.1111/febs.16771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 02/04/2023] [Accepted: 03/03/2023] [Indexed: 03/08/2023]
Abstract
Ocular diseases are a highly heterogeneous group of phenotypes, caused by a spectrum of genetic variants and environmental factors that exhibit diverse clinical symptoms. As a result of its anatomical location, structure and immune privilege, the eye is an ideal system to assess and validate novel genetic therapies. Advances in genome editing have revolutionized the field of biomedical science, enabling researchers to understand the biology behind disease mechanisms and allow the treatment of several health conditions, including ocular pathologies. The advent of clustered regularly interspaced short palindromic repeats (CRISPR)-based gene editing facilitates efficient and specific genetic modifications in the nucleic acid sequence, resulting in permanent changes at the genomic level. This approach has advantages over other treatment strategies and is promising for the treatment of various genetic and non-genetic ocular conditions. This review provides an overview of the CRISPR/CRISPR-associated protein 9 (Cas9) system and summarizes recent advances in the therapeutic application of CRISPR/Cas9 for the treatment of various ocular pathologies, as well as future challenges.
Collapse
Affiliation(s)
| | | | - Bindu Kodati
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX 76107
| | - Charles E. Amankwa
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX 76107
| | - Akash Raola
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX 76107
| | - Gulab Zode
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX 76107
| |
Collapse
|
3
|
Tseng CC, Hung CC, Shu CW, Lee CH, Chen CF, Kuo MS, Kao YY, Chen CL, Ger LP, Liu PF. The Clinical and Biological Effects of Receptor Expression-Enhancing Protein 6 in Tongue Squamous Cell Carcinoma. Biomedicines 2023; 11:biomedicines11051270. [PMID: 37238941 DOI: 10.3390/biomedicines11051270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/07/2023] [Accepted: 04/23/2023] [Indexed: 05/28/2023] Open
Abstract
There are currently no effective biomarkers for the diagnosis and treatment of tongue squamous cell carcinoma (TSCC), which causes a poor 5-year overall survival rate. Thus, it is crucial to identify more effective diagnostic/prognostic biomarkers and therapeutic targets for TSCC patients. The receptor expression-enhancing protein 6 (REEP6), a transmembrane endoplasmic reticulum resident protein, controls the expression or transport of a subset of proteins or receptors. Although it was reported that REEP6 plays a role in lung and colon cancers, its clinical impact and biological role in TSCC are still unknown. The present study aimed to identify a novel effective biomarker and therapeutic target for TSCC patients. Expression levels of REEP6 in specimens from TSCC patients were determined with immunohistochemistry. Gene knockdown was used to evaluate the effects of REEP6 in cancer malignancy (colony/tumorsphere formation, cell cycle regulation, migration, drug resistance and cancer stemness) of TSCC cells. The clinical impact of REEP6 expression and gene co-expression on prognosis were analyzed in oral cancer patients including TSCC patients from The Cancer Genome Atlas database. Tumor tissues had higher levels of REEP6 compared to normal tissues in TSCC patients. Higher REEP6 expression was related to shorter disease-free survival (DFS) in oral cancer patients with poorly differentiated tumor cells. REEP6-knocked-down TSCC cells showed diminished colony/tumorsphere formation, and they also caused G1 arrest and decreased migration, drug resistance and cancer stemness. A high co-expression of REEP6/epithelial-mesenchymal transition or cancer stemness markers also resulted in poor DFS in oral cancer patients. Thus, REEP6 is involved in the malignancy of TSCC and might serve as a potential diagnostic/prognostic biomarker and therapeutic target for TSCC patients.
Collapse
Affiliation(s)
- Chung-Chih Tseng
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
- Department of Dentistry, Zuoying Branch of Kaohsiung Armed Forces General Hospital, Kaohsiung 81342, Taiwan
| | - Chung-Ching Hung
- Department of Otolaryngology, Zuoying Branch of Kaohsiung Armed Forces General Hospital, Kaohsiung 81342, Taiwan
| | - Chih-Wen Shu
- Institute of BioPharmaceutical Sciences, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Cheng-Hsin Lee
- Department of Biomedical Science and Environmental Biology, College of Life Science, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Chun-Feng Chen
- Department of Stomatology, Kaohsiung Veterans General Hospital, Kaohsiung 81362, Taiwan
| | - Mei-Shu Kuo
- Department of Biotechnology, Chia Nan University, Tainan 71710, Taiwan
| | - Yu-Ying Kao
- Department of Biotechnology, Chia Nan University, Tainan 71710, Taiwan
| | - Chun-Lin Chen
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Luo-Ping Ger
- Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung 81362, Taiwan
| | - Pei-Feng Liu
- Department of Biomedical Science and Environmental Biology, College of Life Science, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan
- Center for Cancer Research, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| |
Collapse
|
4
|
Sun Y, Chen L, Xu T, Gou B, Mai JW, Luo DX, Xin WJ, Wu JY. MiR-672-5p-Mediated Upregulation of REEP6 in Spinal Dorsal Horn Participates in Bortezomib-Induced Neuropathic Pain in Rats. Neurochem Res 2023; 48:229-237. [PMID: 36064821 DOI: 10.1007/s11064-022-03741-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 08/19/2022] [Accepted: 08/27/2022] [Indexed: 01/07/2023]
Abstract
Evidence shows that miRNAs are deeply involved in nervous system diseases, but whether miRNAs contribute to the bortezomib (BTZ)-induced neuropathic pain remains unclear. We aimed to investigate whether miRNAs contribute to bortezomib (BTZ)-induced neuropathic pain and explore the related downstream cascades. The level of miRNAs in the spinal dorsal horn was explored using miRNA microarray and PCR. MiR-672-5p was significantly downregulated in dorsal horn neurons in the rats with BTZ treatment. Intrathecal injection of miR-672-5p agomir blunted the increase of the amplitude and frequency of sEPSCs in dorsal horn neurons and mechanical allodynia induced by BTZ. In addition, the knockdown of miR-672-5p by intrathecal injection of antagomir increased the amplitude and frequency of sEPSCs in dorsal horn neurons and decreased the mechanical withdrawal threshold in naïve rats. Furthermore, silico analysis and the data from subsequent assays indicated that REEP6, a potential miR-672-5p-regulating molecule, was increased in the spinal dorsal horn of rats with BTZ-induced neuropathic pain. Blocking REEP6 alleviated the mechanical pain behavior induced by BTZ, whereas overexpressing REEP6 induced pain hypersensitivity in naïve rats. Importantly, we further found that miR-672-5p was expressed in the REEP6-positive cells, and overexpression or knockdown of miR-672-5p reversely regulated the REEP6 expression. Bioinformatics analysis and double-luciferase reporter assay showed the existence of interaction sites between REEP6 mRNA and miR-672-5p. Overall, our study demonstrated that miR-672-5p directly regulated the expression of REEP6, which participated in the neuronal hyperexcitability in the spinal dorsal horn and neuropathic pain following BTZ treatment. This signaling pathway may potentially serve as a novel therapeutic avenue for chemotherapeutic-induced mechanical hypersensitivity.
Collapse
Affiliation(s)
- Yang Sun
- Graduate Department, Department of Sport Medicine, Xi'an Physical Education University, Xi'an, 710068, Shanxi, China.,Department of Rehabilitation Medicine, The Second Affiliated Hospital of Xi'an Medical University, Xi'an, Shanxi, China
| | - Li Chen
- Zhongshan School of Medicine and Guangdong Province Key Laboratory of Brain Function and Disease, Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou, 510080, China
| | - Ting Xu
- Zhongshan School of Medicine and Guangdong Province Key Laboratory of Brain Function and Disease, Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou, 510080, China
| | - Bo Gou
- Graduate Department, Department of Sport Medicine, Xi'an Physical Education University, Xi'an, 710068, Shanxi, China
| | - Jing-Wen Mai
- Department of Anesthesiology, Huizhou Central People's Hospital, Huizhou, 516001, Guangdong, China
| | - De-Xing Luo
- Department of Anesthesiology, Huizhou Central People's Hospital, Huizhou, 516001, Guangdong, China
| | - Wen-Jun Xin
- Zhongshan School of Medicine and Guangdong Province Key Laboratory of Brain Function and Disease, Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou, 510080, China
| | - Jia-Yan Wu
- Zhongshan School of Medicine and Guangdong Province Key Laboratory of Brain Function and Disease, Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou, 510080, China.
| |
Collapse
|
5
|
Fan S, Liu H, Li L. The REEP family of proteins: molecular targets and role in pathophysiology. Pharmacol Res 2022; 185:106477. [PMID: 36191880 DOI: 10.1016/j.phrs.2022.106477] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/27/2022] [Accepted: 09/28/2022] [Indexed: 11/18/2022]
Abstract
Receptor expression-enhancing proteins (REEPs) are an evolutionarily conserved protein family that is pivotal to the structure and function of the endoplasmic reticulum (ER). The REEP family can be classified into two major subfamilies in higher species, the REEP1-4 and REEP5-6 subfamilies. Within the REEP1-4 subfamily, REEP1 and REEP2 are closely related, and REEP3 and REEP4 are similarly related. The REEP family is widely distributed in various tissues. Recent studies indicate that the REEP family is involved in many pathological and physiological processes, such as ER morphogenesis and remodeling, microtubule cytoskeleton regulation, and the trafficking and expression of G protein-coupled receptors (GPCRs). Moreover, the REEP family plays crucial roles in the occurrence and development of many diseases, including neurological diseases, diabetes, retinal diseases, cardiac diseases, infertility, obesity, oligoarticular juvenile idiopathic arthritis (OJIA), COVID-19, and cancer. In the present review, we describe the distribution and structure of the REEP family. Furthermore, we summarize the functions and the associated diseases of this family. Based on the pleiotropic actions of the REEP family, the study of its family members is crucial to understanding the relevant pathophysiological processes and developing strategies to modulate and control these related diseases. AVAILABILITY OF DATA AND MATERIAL: The datasets used or analyzed during the current study are available from the corresponding author on reasonable request.
Collapse
Affiliation(s)
- Sisi Fan
- Institute of Pharmacy and Pharmacology, Hunan Provincial Key Laboratory of tumor microenvironment responsive drug research, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical School, University of South China, Hengyang 421001, Hunan, China
| | - Huimei Liu
- Institute of Pharmacy and Pharmacology, Hunan Provincial Key Laboratory of tumor microenvironment responsive drug research, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical School, University of South China, Hengyang 421001, Hunan, China
| | - Lanfang Li
- Institute of Pharmacy and Pharmacology, Hunan Provincial Key Laboratory of tumor microenvironment responsive drug research, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical School, University of South China, Hengyang 421001, Hunan, China.
| |
Collapse
|
6
|
Tian R, Guo H, Jin Z, Zhang F, Zhao J, Seim I. Molecular evolution of vision-related genes may contribute to marsupial photic niche adaptations. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.982073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Vision plays an essential role in the life of many animals. While most mammals are night-active (nocturnal), many have adapted to novel light environments. This includes diurnal (day-active) and crepuscular (twilight-active) species. Here, we used integrative approaches to investigate the molecular evolution of 112 vision-related genes across 19 genomes representing most marsupial orders. We found that four genes (GUCA1B, GUCY2F, RGR, and SWS2) involved in retinal phototransduction likely became functionally redundant in the ancestor of marsupials, a group of largely obligate nocturnal mammals. We also show evidence of rapid evolution and positive selection of bright-light vision genes in the common ancestor of Macropus (kangaroos, wallaroos, and wallabies). Macropus-specific amino acid substitutions in opsin genes (LWS and SWS1), in particular, may be an adaptation for crepuscular vision in this genus via opsin spectral sensitivity tuning. Our study set the stage for functional genetics studies and provides a stepping stone to future research efforts that fully capture the visual repertoire of marsupials.
Collapse
|
7
|
Albargothy MJ, Azizah NN, Stewart SL, Troendle EP, Steel DHW, Curtis TM, Taggart MJ. Investigation of heterocellular features of the mouse retinal neurovascular unit by 3D electron microscopy. J Anat 2022. [PMID: 35841597 DOI: 10.1111/joa.13721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 06/06/2022] [Accepted: 06/15/2022] [Indexed: 11/26/2022] Open
Abstract
The retina has a complex structure with a diverse collection of component cells that work together to facilitate vision. The retinal capillaries supplying the nutritional requirements to the inner retina have an intricate system of neural, glial and vascular elements that interconnect to form the neurovascular unit (NVU). The retina has no autonomic nervous system and so relies on the NVU as an interdependent, physical and functional unit to alter blood flow appropriately to changes in the physiological environment. The importance of this is demonstrated by alterations in NVU function being apparent in the blinding disease diabetic retinopathy and other diseases of the retina. It is, therefore, imperative to understand the anatomy of the components of the NVU that underlie its functioning and in particular the nanoscale arrangements of its heterocellular components. However, information on this in three spatial dimensions is limited. In the present study, we utilised the technique of serial block-face scanning electron microscopy (SBF-SEM), and computational image reconstruction, to enable the first three-dimensional ultrastructural analysis of the NVU in mouse retinal capillaries. Mouse isolated retina was prepared for SBF-SEM and up to 150 serial scanning electron microscopy images (covering z-axes distances of 12-8 mm) of individual capillaries in the superficial plexus and NVU cellular components digitally aligned. Examination of the data in the x-, y- and z-planes was performed with the use of semi-automated computational image analysis tools including segmentation, 3D image reconstruction and quantitation of cell proximities. A prominent feature of the capillary arrangements in 3D was the extensive sheath-like coverage by singular pericytes. They appeared in close register to the basement membrane with which they interwove in a complex mesh-like appearance. Breaks in the basement membrane appeared to facilitate pericyte interactions with other NVU cell types. There were frequent, close (<10 nm) pericyte-endothelial interactions with direct contact points and peg-and-socket-like morphology. Macroglia typically intervened between neurons and capillary structures; however, regions were identified where neurons came into closer contact with the basement membrane. A software-generated analysis to assess the morphology of the different cellular components of the NVU, including quantifications of convexity, sphericity and cell-to-cell closeness, has enabled preliminary semi-quantitative characterisation of cell arrangements with neighbouring structures. This study presents new data on the nanoscale spatial characteristics of components of the murine retinal NVU in 3D that has implications for our understanding of structural integrity (e.g. pericyte-endothelial cell anchoring) and function (e.g. possible paracrine communication between macroglia and pericytes). It also serves as a platform to inform future studies examining changes in NVU characteristics with different biological and disease circumstances. All raw and processed image data have been deposited for public viewing.
Collapse
Affiliation(s)
- Mona J Albargothy
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Nadhira N Azizah
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Sarah L Stewart
- Wellcome Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - Evan P Troendle
- Wellcome Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - David H W Steel
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Tim M Curtis
- Wellcome Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - Michael J Taggart
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| |
Collapse
|
8
|
Son Y, Choi C, Saha A, Park JH, Im H, Cho YK, Seong JK, Burl RB, Rondini EA, Granneman JG, Lee YH. REEP6 knockout leads to defective β-adrenergic signaling in adipocytes and promotes obesity-related metabolic dysfunction. Metabolism 2022; 130:155159. [PMID: 35150731 DOI: 10.1016/j.metabol.2022.155159] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 01/10/2022] [Accepted: 02/02/2022] [Indexed: 12/11/2022]
Abstract
INTRODUCTION The mobilization and catabolism of lipid energy is a central function of adipocytes that is under the control of the β-adrenergic signaling pathway, and defects in β-adrenergic signaling in adipocytes have been linked to obesity and obesity-related metabolic diseases. Receptor expression-enhancing proteins (REEPs) are endoplasmic reticulum (ER) proteins that play critical roles in subcellular targeting of receptor signaling complexes. Examination of gene expression profiles indicates that, among REEPs expressed in adipocytes, REEP6 expression is uniquely upregulated by sympathetic nervous system activation, suggesting involvement in regulating adrenergic signal transduction. OBJECTIVE The aim of this study was to assess the contribution of REEP6 to the thermogenic activation of adipocytes and characterize the metabolic consequences of REEP6 deficiency in vivo. METHODS Expression levels of Reep6 in adipose tissue were examined by using public transcriptomic data and validated by Western blot and qPCR analyses. Adipocyte-specific regulatory roles of REEP6 were investigated in vitro in C3H10T1/2 adipocytes and in primary adipocytes obtained from REEP6 KO mice. Effects of in vivo REEP6 deficiency on energy expenditure were measured by indirect calorimetry. Mitochondrial content in adipose tissue was accessed by immunoblot, mitochondrial DNA analysis, and confocal and electron microscopy. Effects of REEP6 KO on obesity-induced metabolic dysfunction were tested in a high-fat diet-induced obesity mouse model by glucose tolerance test, Western blot, and histological analyses. RESULTS REEP6 expression is highly enriched in murine adipocytes and is sharply upregulated upon adipocyte differentiation and by cold exposure. Inactivation of REEP6 in mice increased adiposity, and reduced energy expenditure and cold tolerance. REEP6 KO severely reduced protein kinase A-mediated signaling in BAT and greatly reduced mitochondrial mass. The effect of REEP6 inactivation on diminished β-adrenergic signaling was reproduced in cultured adipocytes, indicating that this effect is cell-autonomous. REEP6 KO also suppressed expression of adenylate cyclase 3 (Adcy3) in brown adipose tissue and knockdown of REEP6 in adipocytes reduced targeting of ADCY3 to the plasma membrane. Lastly, REEP6 KO exacerbated high-fat diet-induced insulin resistance and inflammation in adipose tissue. CONCLUSIONS This study indicates that REEP6 plays an important role in β-adrenergic signal transduction in adipocytes involving the expression and trafficking of Adcy3. Genetic inactivation of REEP6 reduces energy expenditure, increases adiposity, and the susceptibility to obesity-related metabolic dysfunction.
Collapse
Affiliation(s)
- Yeonho Son
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Cheoljun Choi
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Abhirup Saha
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Ji-Hyun Park
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Hyeonyeong Im
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Yoon Keun Cho
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Je Kyung Seong
- Korea Mouse Phenotyping Center (KMPC), and Laboratory of Developmental Biology and Genomics, College of Veterinary Medicine, Seoul National University, Seoul, Republic of Korea
| | - Rayanne B Burl
- Center for Molecular Medicine and Genetics, and Center for Integrative Metabolic and Endocrine Research, Wayne State University School of Medicine, Detroit, MI, USA
| | - Elizabeth A Rondini
- Center for Molecular Medicine and Genetics, and Center for Integrative Metabolic and Endocrine Research, Wayne State University School of Medicine, Detroit, MI, USA
| | - James G Granneman
- Center for Molecular Medicine and Genetics, and Center for Integrative Metabolic and Endocrine Research, Wayne State University School of Medicine, Detroit, MI, USA
| | - Yun-Hee Lee
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 08826, Republic of Korea.
| |
Collapse
|
9
|
Lu J, Xiong K, Qian X, Choi J, Shim YK, Burnett J, Mardon G, Chen R. Spata7 is required for maintenance of the retinal connecting cilium. Sci Rep 2022; 12:5575. [PMID: 35368022 PMCID: PMC8976851 DOI: 10.1038/s41598-022-09530-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 03/22/2022] [Indexed: 11/09/2022] Open
Abstract
SPATA7, an early onset LCA3 retinal disease gene, encodes a putative scaffold protein that is essential for the proper assembly of the connecting cilium (CC) complex in photoreceptors. Previous studies have shown that SPATA7 interacts with other photoreceptor-specific ciliary proteins, such as RPGR and RPGRIP1, and maintains the integrity of CC integrity. However, although it is known that Spata7 is required for early formation of the CC, it is unclear if Spata7 is also required for the maintenance of the CC. To investigate Spata7 function in the retina at the adult stage, loss of function was induced in the adult retina upon tamoxifen induction of an inducible Spata7 knockout allele (Spata7flox/-; UbcCreERT2/+). The phenotype of mutant retina was characterized by a combination of histology, immunobiochemistry, and electroretinography (ERG). Our results demonstrated that Spata7 is also essential for maintaining the integrity of the mature retinal CC. Loss of Spata7 in adults caused phenotypes similar to those seen in germline mutant mice, including photoreceptor cell degeneration and defective ERG responses. Close examination of the CC revealed significantly shortened NPHP1 length as a result of Spata7 deletion. Furthermore, mislocalization of rhodopsin, leading to ER stress-mediated apoptosis, was observed in the retinal layers. Our results indicate that Spata7 is required not only for the establishment but also for the maintenance of the CC of photoreceptors.
Collapse
Affiliation(s)
- Jiaxiong Lu
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Kaitlyn Xiong
- Department of Molecular and Human Genetics, Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
| | - Xinye Qian
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Jongsu Choi
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Yoon-Kyung Shim
- Department of Pathology, Baylor College of Medicine, Houston, TX, USA
| | - Jacob Burnett
- Department of Pathology, Baylor College of Medicine, Houston, TX, USA
| | - Graeme Mardon
- Department of Pathology, Baylor College of Medicine, Houston, TX, USA
| | - Rui Chen
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA.
- Department of Molecular and Human Genetics, Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA.
| |
Collapse
|
10
|
McLaughlin T, Medina A, Perkins J, Yera M, Wang JJ, Zhang SX. Cellular stress signaling and the unfolded protein response in retinal degeneration: mechanisms and therapeutic implications. Mol Neurodegener 2022; 17:25. [PMID: 35346303 PMCID: PMC8962104 DOI: 10.1186/s13024-022-00528-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 03/04/2022] [Indexed: 12/22/2022] Open
Abstract
Background The retina, as part of the central nervous system (CNS) with limited capacity for self-reparation and regeneration in mammals, is under cumulative environmental stress due to high-energy demands and rapid protein turnover. These stressors disrupt the cellular protein and metabolic homeostasis, which, if not alleviated, can lead to dysfunction and cell death of retinal neurons. One primary cellular stress response is the highly conserved unfolded protein response (UPR). The UPR acts through three main signaling pathways in an attempt to restore the protein homeostasis in the endoplasmic reticulum (ER) by various means, including but not limited to, reducing protein translation, increasing protein-folding capacity, and promoting misfolded protein degradation. Moreover, recent work has identified a novel function of the UPR in regulation of cellular metabolism and mitochondrial function, disturbance of which contributes to neuronal degeneration and dysfunction. The role of the UPR in retinal neurons during aging and under disease conditions in age-related macular degeneration (AMD), retinitis pigmentosa (RP), glaucoma, and diabetic retinopathy (DR) has been explored over the past two decades. Each of the disease conditions and their corresponding animal models provide distinct challenges and unique opportunities to gain a better understanding of the role of the UPR in the maintenance of retinal health and function. Method We performed an extensive literature search on PubMed and Google Scholar using the following keywords: unfolded protein response, metabolism, ER stress, retinal degeneration, aging, age-related macular degeneration, retinitis pigmentosa, glaucoma, diabetic retinopathy. Results and conclusion We summarize recent advances in understanding cellular stress response, in particular the UPR, in retinal diseases, highlighting the potential roles of UPR pathways in regulation of cellular metabolism and mitochondrial function in retinal neurons. Further, we provide perspective on the promise and challenges for targeting the UPR pathways as a new therapeutic approach in age- and disease-related retinal degeneration.
Collapse
Affiliation(s)
- Todd McLaughlin
- Department of Ophthalmology and Ira G. Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, 955 Main Street, Buffalo, NY, 14203, USA
| | - Andy Medina
- Department of Ophthalmology and Ira G. Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, 955 Main Street, Buffalo, NY, 14203, USA
| | - Jacob Perkins
- Department of Ophthalmology and Ira G. Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, 955 Main Street, Buffalo, NY, 14203, USA
| | - Maria Yera
- Department of Ophthalmology and Ira G. Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, 955 Main Street, Buffalo, NY, 14203, USA.,Neuroscience Program, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Joshua J Wang
- Department of Ophthalmology and Ira G. Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, 955 Main Street, Buffalo, NY, 14203, USA.,Neuroscience Program, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Sarah X Zhang
- Department of Ophthalmology and Ira G. Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, 955 Main Street, Buffalo, NY, 14203, USA. .,Neuroscience Program, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA. .,Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA.
| |
Collapse
|
11
|
Cao Y, Liu K, Xiong Y, Zhao C, Liu L. Increased expression of fragmented tRNA promoted neuronal necrosis. Cell Death Dis 2021; 12:823. [PMID: 34462418 PMCID: PMC8405691 DOI: 10.1038/s41419-021-04108-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 06/26/2021] [Accepted: 06/30/2021] [Indexed: 02/07/2023]
Abstract
Neuronal necrosis induced by excessive glutamate release is well known to contribute morbidity and mortality in ischemic stroke. Over the past decades, strategies on targeting glutamate receptor did not achieve desirable clinical outcomes. Finding the downstream mechanism of the glutamate receptor activation may provide new targets to suppress the cell death. Previously, our study demonstrated that the increase of H3K4 trimethylation (H3K4me3) played a key detrimental role on neuronal necrosis; however, the mechanism of this histone modification is unclear. Through a genome-wide small RNA sequencing, we identified several tRNA-derived fragments (tRFs) and piwi-interacting RNA (piRNAs) species were enriched in glutamate-induced neuronal necrosis in rat primary neuron cultures, and this enrichment was dependent on the H3K4me3 increase. Strikingly, when we transfected several synthesized tRFs and piRNA species into neurons, the tRFs but not the piRNAs induced neuron swelling and death. The cell death morphology recapitulated neuronal necrosis induced by glutamate. For the cytotoxic effect of tRFs, our data suggested that protein synthesis was inhibited likely through induction of ribosomal stalling. By proteomic analysis of tRFs effect, the most affected pathway was enriched in the mitochondrial metabolism. Consistently, mitochondrial fragmentation was increased in neuronal necrosis, and suppression of mitochondrial fission by genetic manipulation or drug rescued neuronal necrosis. Using our previously established Drosophila model of neuronal necrosis, we found that inhibition of small RNA transcription, blocking RNA transport from nucleus to cytosol, or knocking down Ago1/2 to suppress the RNA interference effect, all rescued the fly death, suggesting transcription and processing of small RNAs contribute to neuronal necrosis. Together, these results indicate that the abnormal transcription of tRFs may play a key role downstream of the H3K4me3 increase. This provides a potential new strategy to suppress neuronal necrosis.
Collapse
Affiliation(s)
- Yanyan Cao
- grid.24696.3f0000 0004 0369 153XDepartment of Biochemistry and Molecular Biology School of Basic Medicine, Capital Medical University, Youanmen, Beijing, China ,grid.453074.10000 0000 9797 0900Department of Neurology, First Affiliated Hospital, and College of Clinical Medicine of Henan University of Science and Technology, Luoyang, China
| | - Kai Liu
- grid.49470.3e0000 0001 2331 6153College of Life Sciences, Wuhan University, Wuhan, China
| | - Ying Xiong
- grid.24696.3f0000 0004 0369 153XDepartment of Biochemistry and Molecular Biology School of Basic Medicine, Capital Medical University, Youanmen, Beijing, China
| | - Chunyue Zhao
- grid.64939.310000 0000 9999 1211Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University, Beijing, China
| | - Lei Liu
- grid.24696.3f0000 0004 0369 153XDepartment of Biochemistry and Molecular Biology School of Basic Medicine, Capital Medical University, Youanmen, Beijing, China
| |
Collapse
|
12
|
Liang Q, Wu N, Zaneveld S, Liu H, Fu S, Wang K, Bertrand R, Wang J, Li Y, Chen R. Transcript isoforms of Reep6 have distinct functions in the retina. Hum Mol Genet 2021; 30:1907-1918. [PMID: 34104971 DOI: 10.1093/hmg/ddab157] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/30/2021] [Accepted: 05/31/2021] [Indexed: 12/21/2022] Open
Abstract
Much of the complexity of the eukaryotic cell transcriptome is due to the alternative splicing of mRNA. However, knowledge on how transcriptome complexity is translated into functional complexity remains limited. For example, although different isoforms of a gene may show distinct temporal and spatial expression patterns, it is largely unknown whether these isoforms encode proteins with distinct functions matching their expression pattern. In this report, we investigated the function and relationship of the two isoforms of Reep6, namely Reep6.1 and Reep6.2, in rod photoreceptor cells. These two isoforms result from the alternative splicing of exon 5 and show mutually exclusive expression patterns. Reep6.2 is the canonical isoform that is expressed in non-retinal tissues while Reep6.1 is the only expressed isoform in the adult retina. The Reep6.1 isoform-specific knockout mouse, Reep6E5/E5, is generated by deleting exon 5 and a homozygous deletion phenotypically displayed a rod degeneration phenotype comparable to a Reep6 full knockout mouse, indicating that the Reep6.1 isoform is essential for the rod photoreceptor cell survival. Consistent with the results obtained from a loss-of-function experiment, overexpression of Reep6.2 failed to rescue the rod degeneration phenotype of Reep6 knockout mice while overexpression of Reep6.1 does lead to rescue. These results demonstrate that, consistent with the expression pattern of the isoform, Reep6.1 has rod-specific functions that cannot be substituted by its canonical isoform. Our findings suggested that a strict regulation of splicing is required for the maintenance of photoreceptor cells.
Collapse
Affiliation(s)
- Qingnan Liang
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA.,Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Nathaniel Wu
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Smriti Zaneveld
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Hehe Liu
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Shangyi Fu
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Keqing Wang
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Renae Bertrand
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA.,Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Jun Wang
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Yumei Li
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Rui Chen
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA.,Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, 77030, USA
| |
Collapse
|
13
|
Zhang L, Li Y, Qin L, Wu Y, Lei B. Autosomal Recessive Retinitis Pigmentosa Associated with Three Novel REEP6 Variants in Chinese Population. Genes (Basel) 2021; 12:genes12040537. [PMID: 33917198 PMCID: PMC8068040 DOI: 10.3390/genes12040537] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 03/25/2021] [Accepted: 03/27/2021] [Indexed: 11/28/2022] Open
Abstract
Retinitis pigmentosa 77 is caused by mutations of REEP6 (MIM: 609346), which encodes a protein for the development of photoreceptors. Our study was to identify disease-causing variants in three Chinese families using targeted next-generation sequencing (NGS). Multiple lines of computational predictions combined with in vitro cellular experiments were applied to evaluate the pathogenicity of the newly found variants. Three novel variants in REEP6, including one missense variant, c.268G>C, one frameshift variant, c.468delC, and one splicing variant, c.598+1G>C, were found, while c.268G>C was detected in all probands. The three variants were classified as likely pathogenic by the American College of Medical Genetics and Genomics (ACMG). REEP6 variant proteins c.268G>C and c.468delC in cultured cells destabilized the REEP6 protein and induced intracellular inclusions. Our data suggested that REEP6 c.268G>C may be a recurrent causative variant in Chinese autosomal recessive retinitis pigmentosa patients.
Collapse
Affiliation(s)
- Lujia Zhang
- Graduate School, Xinxiang Medical University, Xinxiang 453003, China;
- Henan Clinical Research Center for Ophthalmic Diseases, Henan Branch of National Clinical Research Center for Ocular Diseases, Henan Eye Institute, Henan Eye Hospital, Zhengzhou University People’s Hospital, Henan Provincial People’s Hospital, Zhengzhou 450003, China;
| | - Ya Li
- Henan Clinical Research Center for Ophthalmic Diseases, Henan Branch of National Clinical Research Center for Ocular Diseases, Henan Eye Institute, Henan Eye Hospital, Zhengzhou University People’s Hospital, Henan Provincial People’s Hospital, Zhengzhou 450003, China;
| | - Litao Qin
- Henan Medical Genetics Institute, Henan Provincial Key Laboratory of Genetic Diseases and Functional Genomics, People’s Hospital of Zhengzhou University, Zhengzhou, Henan 450003, China;
| | - Yu Wu
- Shanghai Flash Interpretation Biotechnology, Shanghai 201615, China;
| | - Bo Lei
- Henan Clinical Research Center for Ophthalmic Diseases, Henan Branch of National Clinical Research Center for Ocular Diseases, Henan Eye Institute, Henan Eye Hospital, Zhengzhou University People’s Hospital, Henan Provincial People’s Hospital, Zhengzhou 450003, China;
- Correspondence:
| |
Collapse
|
14
|
Newton F, Megaw R. Mechanisms of Photoreceptor Death in Retinitis Pigmentosa. Genes (Basel) 2020; 11:genes11101120. [PMID: 32987769 PMCID: PMC7598671 DOI: 10.3390/genes11101120] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 09/15/2020] [Accepted: 09/22/2020] [Indexed: 02/08/2023] Open
Abstract
Retinitis pigmentosa (RP) is the most common cause of inherited blindness and is characterised by the progressive loss of retinal photoreceptors. However, RP is a highly heterogeneous disease and, while much progress has been made in developing gene replacement and gene editing treatments for RP, it is also necessary to develop treatments that are applicable to all causative mutations. Further understanding of the mechanisms leading to photoreceptor death is essential for the development of these treatments. Recent work has therefore focused on the role of apoptotic and non-apoptotic cell death pathways in RP and the various mechanisms that trigger these pathways in degenerating photoreceptors. In particular, several recent studies have begun to elucidate the role of microglia and innate immune response in the progression of RP. Here, we discuss some of the recent progress in understanding mechanisms of rod and cone photoreceptor death in RP and summarise recent clinical trials targeting these pathways.
Collapse
Affiliation(s)
- Fay Newton
- MRC Human Genetics Unit, University of Edinburgh, South Bridge, Edinburgh EH8 9YL, UK;
- Correspondence:
| | - Roly Megaw
- MRC Human Genetics Unit, University of Edinburgh, South Bridge, Edinburgh EH8 9YL, UK;
- Princess Alexandra Eye Pavilion, NHS Lothian, Edinburgh EH3 9HA, UK
| |
Collapse
|
15
|
Shi X, Hai L, Govindasamy K, Gao J, Coppens I, Hu J, Wang Q, Bhanot P. A Plasmodium homolog of ER tubule-forming proteins is required for parasite virulence. Mol Microbiol 2020; 114:454-467. [PMID: 32432369 DOI: 10.1111/mmi.14526] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 05/04/2020] [Accepted: 05/05/2020] [Indexed: 01/27/2023]
Abstract
Reticulon and REEP family of proteins stabilize the high curvature of endoplasmic reticulum (ER) tubules. Plasmodium berghei Yop1 (PbYop1) is a REEP5 homolog in Plasmodium. Here, we characterize its function using a gene-knockout (Pbyop1∆). Pbyop1∆ asexual stage parasites display abnormal ER architecture and an enlarged digestive vacuole. The erythrocytic cycle of Pbyop1∆ parasites is severely attenuated and the incidence of experimental cerebral malaria is significantly decreased in Pbyop1∆-infected mice. Pbyop1∆ sporozoites have reduced speed, are slower to invade host cells but give rise to equal numbers of infected HepG2 cells, as WT sporozoites. We propose that PbYOP1's disruption may lead to defects in trafficking and secretion of a subset of proteins required for parasite development and invasion of erythrocytes. Furthermore, the maintenance of ER morphology in different parasite stages is likely to depend on different proteins.
Collapse
Affiliation(s)
- Xiaoyu Shi
- Department of Immunology, School of Basic Medical Sciences, Tianjin Key Laboratory of Cellular and Molecular Immunology, Key Laboratory of Immune Microenvironment and Diseases of Educational Ministry of China, Tianjin Medical University, Tianjin, China
| | - Lei Hai
- Department of Immunology, School of Basic Medical Sciences, Tianjin Key Laboratory of Cellular and Molecular Immunology, Key Laboratory of Immune Microenvironment and Diseases of Educational Ministry of China, Tianjin Medical University, Tianjin, China
| | - Kavitha Govindasamy
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Jian Gao
- Department of Immunology, School of Basic Medical Sciences, Tianjin Key Laboratory of Cellular and Molecular Immunology, Key Laboratory of Immune Microenvironment and Diseases of Educational Ministry of China, Tianjin Medical University, Tianjin, China
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - Junjie Hu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Qian Wang
- Department of Immunology, School of Basic Medical Sciences, Tianjin Key Laboratory of Cellular and Molecular Immunology, Key Laboratory of Immune Microenvironment and Diseases of Educational Ministry of China, Tianjin Medical University, Tianjin, China.,National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Purnima Bhanot
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, NJ, USA
| |
Collapse
|
16
|
Application of CRISPR Tools for Variant Interpretation and Disease Modeling in Inherited Retinal Dystrophies. Genes (Basel) 2020; 11:genes11050473. [PMID: 32349249 PMCID: PMC7290804 DOI: 10.3390/genes11050473] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 04/23/2020] [Accepted: 04/23/2020] [Indexed: 12/27/2022] Open
Abstract
Inherited retinal dystrophies are an assorted group of rare diseases that collectively account for the major cause of visual impairment of genetic origin worldwide. Besides clinically, these vision loss disorders present a high genetic and allelic heterogeneity. To date, over 250 genes have been associated to retinal dystrophies with reported causative variants of every nature (nonsense, missense, frameshift, splice-site, large rearrangements, and so forth). Except for a fistful of mutations, most of them are private and affect one or few families, making it a challenge to ratify the newly identified candidate genes or the pathogenicity of dubious variants in disease-associated loci. A recurrent option involves altering the gene in in vitro or in vivo systems to contrast the resulting phenotype and molecular imprint. To validate specific mutations, the process must rely on simulating the precise genetic change, which, until recently, proved to be a difficult endeavor. The rise of the CRISPR/Cas9 technology and its adaptation for genetic engineering now offers a resourceful suite of tools to alleviate the process of functional studies. Here we review the implementation of these RNA-programmable Cas9 nucleases in culture-based and animal models to elucidate the role of novel genes and variants in retinal dystrophies.
Collapse
|
17
|
Devlin DJ, Agrawal Zaneveld S, Nozawa K, Han X, Moye AR, Liang Q, Harnish JM, Matzuk MM, Chen R. Knockout of mouse receptor accessory protein 6 leads to sperm function and morphology defects†. Biol Reprod 2020; 102:1234-1247. [PMID: 32101290 DOI: 10.1093/biolre/ioaa024] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 12/31/2019] [Accepted: 05/26/2020] [Indexed: 02/07/2023] Open
Abstract
Receptor accessory protein 6 (REEP6) is a member of the REEP/Ypt-interacting protein family that we recently identified as essential for normal endoplasmic reticulum homeostasis and protein trafficking in the retina of mice and humans. Interestingly, in addition to the loss of REEP6 in our knockout (KO) mouse model recapitulating the retinal degeneration of humans with REEP6 mutations causing retinitis pigmentosa (RP), we also found that male mice are sterile. Herein, we characterize the infertility caused by loss of Reep6. Expression of both Reep6 mRNA transcripts is present in the testis; however, isoform 1 becomes overexpressed during spermiogenesis. In vitro fertilization assays reveal that Reep6 KO spermatozoa are able to bind the zona pellucida but are only able to fertilize oocytes lacking the zona pellucida. Although spermatogenesis appears normal in KO mice, cauda epididymal spermatozoa have severe motility defects and variable morphological abnormalities, including bent or absent tails. Immunofluorescent staining reveals that REEP6 expression first appears in stage IV tubules within step 15 spermatids, and REEP6 localizes to the connecting piece, midpiece, and annulus of mature spermatozoa. These data reveal an important role for REEP6 in sperm motility and morphology and is the first reported function for a REEP protein in reproductive processes. Additionally, this work identifies a new gene potentially responsible for human infertility and has implications for patients with RP harboring mutations in REEP6.
Collapse
Affiliation(s)
- Darius J Devlin
- Interdepartmental Program in Translational Biology & Molecular Medicine, Baylor College of Medicine, Houston, TX, USA.,Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
| | - Smriti Agrawal Zaneveld
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Kaori Nozawa
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA.,Center for Drug Discovery, Baylor College of Medicine, Houston, TX, USA
| | - Xiao Han
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.,Reproductive Medical Center, People's Hospital of Zhengzhou University, Zhengzhou, China
| | - Abigail R Moye
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Qingnan Liang
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.,Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Jacob Michael Harnish
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Martin M Matzuk
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.,Center for Drug Discovery, Baylor College of Medicine, Houston, TX, USA
| | - Rui Chen
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| |
Collapse
|
18
|
RD Genes Associated with High Photoreceptor cGMP-Levels (Mini-Review). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1185:245-249. [PMID: 31884619 DOI: 10.1007/978-3-030-27378-1_40] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Many RD-causing mutations lead to a dysregulation of cyclic guanosine monophosphate (cGMP), making cGMP signalling a prime target for the development of new treatment approaches. We showed previously that an analogue of cGMP, which inhibited cGMP signalling targets, increased photoreceptor viability in three rodent RD models carrying different genetic defects, in different RD genes. This raises the question of the possible generality of this approach as a treatment for RD. Here, we review RD genes that can be associated with high cGMP and discuss which RD genes might be amenable to a treatment aimed at inhibiting excessive cGMP signalling.
Collapse
|
19
|
Cataloguing and Selection of mRNAs Localized to Dendrites in Neurons and Regulated by RNA-Binding Proteins in RNA Granules. Biomolecules 2020; 10:biom10020167. [PMID: 31978946 PMCID: PMC7072219 DOI: 10.3390/biom10020167] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/18/2020] [Accepted: 01/20/2020] [Indexed: 12/15/2022] Open
Abstract
Spatiotemporal translational regulation plays a key role in determining cell fate and function. Specifically, in neurons, local translation in dendrites is essential for synaptic plasticity and long-term memory formation. To achieve local translation, RNA-binding proteins in RNA granules regulate target mRNA stability, localization, and translation. To date, mRNAs localized to dendrites have been identified by comprehensive analyses. In addition, mRNAs associated with and regulated by RNA-binding proteins have been identified using various methods in many studies. However, the results obtained from these numerous studies have not been compiled together. In this review, we have catalogued mRNAs that are localized to dendrites and are associated with and regulated by the RNA-binding proteins fragile X mental retardation protein (FMRP), RNA granule protein 105 (RNG105, also known as Caprin1), Ras-GAP SH3 domain binding protein (G3BP), cytoplasmic polyadenylation element binding protein 1 (CPEB1), and staufen double-stranded RNA binding proteins 1 and 2 (Stau1 and Stau2) in RNA granules. This review provides comprehensive information on dendritic mRNAs, the neuronal functions of mRNA-encoded proteins, the association of dendritic mRNAs with RNA-binding proteins in RNA granules, and the effects of RNA-binding proteins on mRNA regulation. These findings provide insights into the mechanistic basis of protein-synthesis-dependent synaptic plasticity and memory formation and contribute to future efforts to understand the physiological implications of local regulation of dendritic mRNAs in neurons.
Collapse
|
20
|
Joe MK, Li W, Hiriyanna S, Yu W, Shah SA, Abu-Asab M, Qian H, Wu Z. A Common Outer Retinal Change in Retinal Degeneration by Optical Coherence Tomography Can Be Used to Assess Outcomes of Gene Therapy. Hum Gene Ther 2019; 30:1520-1530. [PMID: 31672061 DOI: 10.1089/hum.2019.162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Identifying early disease hallmarks in animal models with slow disease progression may expedite disease detection and assessment of treatment outcomes. Using optical coherence tomography, a widely applied noninvasive method for monitoring retinal structure changes, we analyzed retinal optical sections from six mouse lines with retinal degeneration caused by mutations in different disease-causing genes. While images from wild-type mice revealed four well-separated hyper-reflective bands in the outer retina (designated as outer retina reflective bands, ORRBs) at all ages, the second band (ORRB2) and the third band (ORRB3) were merged in retinas of five mutant mouse lines at early ages, suggesting the pathological nature of this alteration. This ORRB change appeared to be degenerating photoreceptor related, and occurred before obvious morphological changes that can be identified on both hematoxylin and eosin-stained sections and electron microscopic sections. Importantly, the merging of ORRB2 and ORRB3 was reversed by treatment with adeno-associated viral vector-mediated gene replacement therapies, and this restoration occurred much earlier than measurable functional or structural improvement. Our data suggest that the ORRB change could be a common hallmark of early retinal degeneration and its restoration could be used for rapid and noninvasive assessment of therapeutic effects following gene therapy or other treatment interventions.
Collapse
Affiliation(s)
- Myung Kuk Joe
- Ocular Gene Therapy Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Wenbo Li
- Ocular Gene Therapy Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Suja Hiriyanna
- Ocular Gene Therapy Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Wenhan Yu
- Ocular Gene Therapy Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Shreya A Shah
- Ocular Gene Therapy Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Mones Abu-Asab
- Histopathology Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Haohua Qian
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Zhijian Wu
- Ocular Gene Therapy Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland
| |
Collapse
|
21
|
Blond F, Léveillard T. Functional Genomics of the Retina to Elucidate its Construction and Deconstruction. Int J Mol Sci 2019; 20:E4922. [PMID: 31590277 PMCID: PMC6801968 DOI: 10.3390/ijms20194922] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 10/01/2019] [Indexed: 12/20/2022] Open
Abstract
The retina is the light sensitive part of the eye and nervous tissue that have been used extensively to characterize the function of the central nervous system. The retina has a central position both in fundamental biology and in the physiopathology of neurodegenerative diseases. We address the contribution of functional genomics to the understanding of retinal biology by reviewing key events in their historical perspective as an introduction to major findings that were obtained through the study of the retina using genomics, transcriptomics and proteomics. We illustrate our purpose by showing that most of the genes of interest for retinal development and those involved in inherited retinal degenerations have a restricted expression to the retina and most particularly to photoreceptors cells. We show that the exponential growth of data generated by functional genomics is a future challenge not only in terms of storage but also in terms of accessibility to the scientific community of retinal biologists in the future. Finally, we emphasize on novel perspectives that emerge from the development of redox-proteomics, the new frontier in retinal biology.
Collapse
Affiliation(s)
- Frédéric Blond
- Department of Genetics, Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, F-75012 Paris, France.
| | - Thierry Léveillard
- Department of Genetics, Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, F-75012 Paris, France.
| |
Collapse
|
22
|
Lin Y, Xu CL, Velez G, Yang J, Tanaka AJ, Breazzano MP, Mahajan VB, Sparrow JR, Tsang SH. Novel REEP6 gene mutation associated with autosomal recessive retinitis pigmentosa. Doc Ophthalmol 2019; 140:67-75. [PMID: 31538292 DOI: 10.1007/s10633-019-09719-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 09/04/2019] [Indexed: 01/06/2023]
Abstract
PURPOSE This study reports the ophthalmic and genetic findings of a Cameroonian patient with autosomal recessive retinitis pigmentosa (arRP) caused by a novel Receptor Expression Enhancing Protein 6 (REEP6) homozygous mutation. PATIENT AND METHODS A 33-year-old man underwent comprehensive ophthalmic examinations, including visual acuity measurements, dilated fundus imaging, electroretinography (ERG), and spectral-domain optical coherence tomography (SD-OCT). Short-wavelength fundus autofluorescence (SW-AF) and near-infrared fundus autofluorescence (NIR-AF) were also evaluated. Whole exome sequencing (WES) was used to identify potential pathogenic variants. RESULTS Fundus examination revealed typical RP findings with additional temporal ten micron yellow dots. SD-OCT imaging revealed cystoid macular edema and perifoveal outer retinal atrophy with centrally preserved inner segment ellipsoid zone (EZ) bands. Hyperreflective spots were seen in the inner retinal layers. On SW-AF images, a hypoautofluorescent area in the perifoveal area was observed. NIR-AF imaging revealed an irregularly shaped hyperautofluorescent ring. His visual acuity was mildly affected. ERG showed undetectable rod responses and intact cone responses. Genetic testing via WES revealed a novel homozygous mutation (c.295G>A, p.Glu99Lys) in the gene encoding REEP6, which is predicted to alter the charge in the transmembrane helix. CONCLUSIONS This report is not only the first description of a Cameroonian patient with arRP associated with a REEP6 mutation, but also this particular genetic alteration. Substitution of p.Glu99Lys in REEP6 likely disrupts the interactions between REEP6 and the ER membrane. NIR-AF imaging may be particularly useful for assessing functional photoreceptor cells and show an "avocado" pattern of hyperautofluorescence in patients with the REEP6 mutation.
Collapse
Affiliation(s)
- Yuchen Lin
- Jonas Children's Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, Columbia Stem Cell Initiative, Departments of Ophthalmology, Pathology and Cell Biology, Institute of Human Nutrition, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA.,Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Christine L Xu
- Jonas Children's Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, Columbia Stem Cell Initiative, Departments of Ophthalmology, Pathology and Cell Biology, Institute of Human Nutrition, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
| | - Gabriel Velez
- Omics Laboratory, Department of Ophthalmology, Byers Eye Institute, Stanford University, Palo Alto, CA, USA.,Medical Scientist Training Program, University of Iowa, Iowa City, IA, USA
| | - Jing Yang
- Omics Laboratory, Department of Ophthalmology, Byers Eye Institute, Stanford University, Palo Alto, CA, USA
| | - Akemi J Tanaka
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Mark P Breazzano
- Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA.,Department of Ophthalmology, New York University School of Medicine, New York, NY, USA
| | - Vinit B Mahajan
- Omics Laboratory, Department of Ophthalmology, Byers Eye Institute, Stanford University, Palo Alto, CA, USA.,Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Janet R Sparrow
- Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA.,Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Stephen H Tsang
- Jonas Children's Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, Columbia Stem Cell Initiative, Departments of Ophthalmology, Pathology and Cell Biology, Institute of Human Nutrition, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA. .,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA.
| |
Collapse
|
23
|
Méjécase C, Mohand-Saïd S, El Shamieh S, Antonio A, Condroyer C, Blanchard S, Letexier M, Saraiva JP, Sahel JA, Audo I, Zeitz C. A novel nonsense variant in REEP6 is involved in a sporadic rod-cone dystrophy case. Clin Genet 2019; 93:707-711. [PMID: 29120066 DOI: 10.1111/cge.13171] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 11/03/2017] [Accepted: 11/05/2017] [Indexed: 12/22/2022]
Abstract
Rod-cone dystrophy (RCD), also called retinitis pigmentosa, is the most common form of progressive inherited retinal disorders secondary to photoreceptor degeneration. It is a genetically heterogeneous disease characterized by night blindness, followed by visual field constriction and, in most severe cases, total blindness. The aim of our study was to identify the underlying gene defect leading to severe RCD in a 60-year-old woman. The patient's DNA was investigated by targeted next generation sequencing followed by whole exome sequencing. A novel nonsense variant, c.267G>A p.(Trp89*), was identified at a homozygous state in the proband in REEP6 gene, recently reported mutated in 7 unrelated families with RCD. Further functional studies will help to understand the physiopathology associated with REEP6 mutations that may be linked to a protein trafficking defect.
Collapse
Affiliation(s)
- C Méjécase
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - S Mohand-Saïd
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC 1423, Paris, France
| | - S El Shamieh
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,Department of Medical Laboratory Technology, Faculty of Health Sciences, Beirut Arab University, Beirut, Lebanon
| | - A Antonio
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC 1423, Paris, France
| | - C Condroyer
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - S Blanchard
- IntegraGen SA, Genopole Campus, Evry, France
| | - M Letexier
- IntegraGen SA, Genopole Campus, Evry, France
| | - J-P Saraiva
- IntegraGen SA, Genopole Campus, Evry, France
| | - J-A Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC 1423, Paris, France.,Institute of Ophthalmology, University College of London, London, UK.,Fondation Ophtalmologique Adolphe de Rothschild, Paris, France.,Academie des Sciences, Institut de France, Paris, France.,Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburg, Pennsylvania, USA
| | - I Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC 1423, Paris, France.,Institute of Ophthalmology, University College of London, London, UK
| | - C Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| |
Collapse
|
24
|
Power M, Das S, Schütze K, Marigo V, Ekström P, Paquet-Durand F. Cellular mechanisms of hereditary photoreceptor degeneration - Focus on cGMP. Prog Retin Eye Res 2019; 74:100772. [PMID: 31374251 DOI: 10.1016/j.preteyeres.2019.07.005] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 07/25/2019] [Accepted: 07/29/2019] [Indexed: 12/21/2022]
Abstract
The cellular mechanisms underlying hereditary photoreceptor degeneration are still poorly understood, a problem that is exacerbated by the enormous genetic heterogeneity of this disease group. However, the last decade has yielded a wealth of new knowledge on degenerative pathways and their diversity. Notably, a central role of cGMP-signalling has surfaced for photoreceptor cell death triggered by a subset of disease-causing mutations. In this review, we examine key aspects relevant for photoreceptor degeneration of hereditary origin. The topics covered include energy metabolism, epigenetics, protein quality control, as well as cGMP- and Ca2+-signalling, and how the related molecular and metabolic processes may trigger photoreceptor demise. We compare and integrate evidence on different cell death mechanisms that have been associated with photoreceptor degeneration, including apoptosis, necrosis, necroptosis, and PARthanatos. A special focus is then put on the mechanisms of cGMP-dependent cell death and how exceedingly high photoreceptor cGMP levels may cause activation of Ca2+-dependent calpain-type proteases, histone deacetylases and poly-ADP-ribose polymerase. An evaluation of the available literature reveals that a large group of patients suffering from hereditary photoreceptor degeneration carry mutations that are likely to trigger cGMP-dependent cell death, making this pathway a prime target for future therapy development. Finally, an outlook is given into technological and methodological developments that will with time likely contribute to a comprehensive overview over the entire metabolic complexity of photoreceptor cell death. Building on such developments, new imaging technology and novel biomarkers may be used to develop clinical test strategies, that fully consider the genetic heterogeneity of hereditary retinal degenerations, in order to facilitate clinical testing of novel treatment approaches.
Collapse
Affiliation(s)
- Michael Power
- Cell Death Mechanism Group, Institute for Ophthalmic Research, University of Tübingen, Germany; Centre for Integrative Neurosciences (CIN), University of Tübingen, Germany; Graduate Training Centre of Neuroscience (GTC), University of Tübingen, Germany
| | - Soumyaparna Das
- Cell Death Mechanism Group, Institute for Ophthalmic Research, University of Tübingen, Germany; Graduate Training Centre of Neuroscience (GTC), University of Tübingen, Germany
| | | | - Valeria Marigo
- Department of Life Sciences, University of Modena and Reggio Emilia, Italy
| | - Per Ekström
- Ophthalmology, Department of Clinical Sciences Lund, Faculty of Medicine, Lund University, Sweden
| | - François Paquet-Durand
- Cell Death Mechanism Group, Institute for Ophthalmic Research, University of Tübingen, Germany.
| |
Collapse
|
25
|
Ma H, Yang F, Butler MR, Rapp J, Le YZ, Ding XQ. Ryanodine Receptor 2 Contributes to Impaired Protein Localization in Cyclic Nucleotide-Gated Channel Deficiency. eNeuro 2019; 6:ENEURO.0119-19.2019. [PMID: 31182474 PMCID: PMC6597858 DOI: 10.1523/eneuro.0119-19.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/20/2019] [Accepted: 05/21/2019] [Indexed: 01/28/2023] Open
Abstract
The photoreceptor cyclic nucleotide-gated (CNG) channel plays a pivotal role in phototransduction and cellular calcium homeostasis. Mutations in the cone photoreceptor CNG channel subunits CNGA3 and CNGB3 are associated with achromatopsia and cone dystrophies. CNG channel deficiency leads to endoplasmic reticulum (ER) stress-associated cone apoptosis, protein mislocalization, and ER calcium dysregulation. This work investigated the potential mechanisms of protein mislocalization associated with ER calcium dysregulation using Cnga3-/- mice lacking ER Ca2+ channel ryanodine receptor 2 (RyR2) specifically in cones. Deletion of Ryr2 improved outer segment (OS) localization of the cone proteins M-opsin, S-opsin, and cone phosphodiesterase subunit α' (PDE6C) and decreased inner segment localization. One-month-old Cnga3-/- mice showed ∼30% of M-opsin, 55% of S-opsin, and 50% of PDE6C localized to the OS. Cnga3-/- mice with Ryr2 deletion at the same age showed almost 60% of M-opsin, 70% of S-opsin, and 70% of PDE6C localized to the OS. Deletion of Ryr2 nearly completely reversed elevations of the ER stress markers phospho-IRE1α and phospho-eIF2α and suppressed cone apoptosis. Consistent with the improved cone protein localization and reduced ER stress/cone apoptosis, cone survival was improved by deletion of Ryr2 The number of cones was increased by ∼28% in 2- to 4-month-old Cnga3-/- mice with Ryr2 deletion compared with age-matched Cnga3-/- mice. This work demonstrates a role of RyR2/ER calcium dysregulation in protein mislocalization, ER stress, and cone death. The findings provide novel insights into the mechanisms of photoreceptor degeneration and support strategies targeting ER calcium regulation to manage retinal degeneration.
Collapse
Affiliation(s)
- Hongwei Ma
- Department of Cell Biology, University of Oklahoma Health Sciences Center (OUHSC), Oklahoma City, Oklahoma 73104
| | - Fan Yang
- Department of Cell Biology, University of Oklahoma Health Sciences Center (OUHSC), Oklahoma City, Oklahoma 73104
| | - Michael R Butler
- Department of Cell Biology, University of Oklahoma Health Sciences Center (OUHSC), Oklahoma City, Oklahoma 73104
| | - Jacob Rapp
- Department of Cell Biology, University of Oklahoma Health Sciences Center (OUHSC), Oklahoma City, Oklahoma 73104
| | - Yun-Zheng Le
- Department of Cell Biology, University of Oklahoma Health Sciences Center (OUHSC), Oklahoma City, Oklahoma 73104
- Department of Medicine, University of Oklahoma Health Sciences Center (OUHSC), Oklahoma City, Oklahoma 73104
- Department of Ophthalmology, University of Oklahoma Health Sciences Center (OUHSC), Oklahoma City, Oklahoma 73104
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center (OUHSC), Oklahoma City, Oklahoma 73104
| | - Xi-Qin Ding
- Department of Cell Biology, University of Oklahoma Health Sciences Center (OUHSC), Oklahoma City, Oklahoma 73104
| |
Collapse
|
26
|
Abstract
Rods and cones are retinal photoreceptor neurons required for our visual sensation. Because of their highly polarized structures and well-characterized processes of G protein-coupled receptor-mediated phototransduction signaling, these photoreceptors have been excellent models for studying the compartmentalization and sorting of proteins. Rods and cones have a modified ciliary compartment called the outer segment (OS) as well as non-OS compartments. The distinct membrane protein compositions between OS and non-OS compartments suggest that the OS is separated from the rest of the cellular compartments by multiple barriers or gates that are selectively permissive to specific cargoes. This review discusses the mechanisms of protein sorting and compartmentalization in photoreceptor neurons. Proper sorting and compartmentalization of membrane proteins are required for signal transduction and transmission. This review also discusses the roles of compartmentalized signaling, which is compromised in various retinal ciliopathies.
Collapse
Affiliation(s)
- Yoshikazu Imanishi
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106, USA;
| |
Collapse
|
27
|
Generation, transcriptome profiling, and functional validation of cone-rich human retinal organoids. Proc Natl Acad Sci U S A 2019; 116:10824-10833. [PMID: 31072937 DOI: 10.1073/pnas.1901572116] [Citation(s) in RCA: 113] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Rod and cone photoreceptors are light-sensing cells in the human retina. Rods are dominant in the peripheral retina, whereas cones are enriched in the macula, which is responsible for central vision and visual acuity. Macular degenerations affect vision the most and are currently incurable. Here we report the generation, transcriptome profiling, and functional validation of cone-rich human retinal organoids differentiated from hESCs using an improved retinal differentiation system. Induced by extracellular matrix, aggregates of hESCs formed single-lumen cysts composed of epithelial cells with anterior neuroectodermal/ectodermal fates, including retinal cell fate. Then, the cysts were en bloc-passaged, attached to culture surface, and grew, forming colonies in which retinal progenitor cell patches were found. Following gentle cell detachment, retinal progenitor cells self-assembled into retinal epithelium-retinal organoid-that differentiated into stratified cone-rich retinal tissue in agitated cultures. Electron microscopy revealed differentiating outer segments of photoreceptor cells. Bulk RNA-sequencing profiling of time-course retinal organoids demonstrated that retinal differentiation in vitro recapitulated in vivo retinogenesis in temporal expression of cell differentiation markers and retinal disease genes, as well as in mRNA alternative splicing. Single-cell RNA-sequencing profiling of 8-mo retinal organoids identified cone and rod cell clusters and confirmed the cone enrichment initially revealed by quantitative microscopy. Notably, cones from retinal organoids and human macula had similar single-cell transcriptomes, and so did rods. Cones in retinal organoids exhibited electrophysiological functions. Collectively, we have established cone-rich retinal organoids and a reference of transcriptomes that are valuable resources for retinal studies.
Collapse
|
28
|
Zaneveld SA, Eblimit A, Liang Q, Bertrand R, Wu N, Liu H, Nguyen Q, Zaneveld J, Wang K, Li Y, Chen R. Gene Therapy Rescues Retinal Degeneration in Receptor Expression-Enhancing Protein 6 Mutant Mice. Hum Gene Ther 2018; 30:302-315. [PMID: 30101608 PMCID: PMC6437630 DOI: 10.1089/hum.2018.078] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Hereditary retinal dystrophy is clinically defined as a broad group of chronic and progressive disorders that affect visual function by causing photoreceptor degeneration. Previously, we identified mutations in the gene encoding receptor expression-enhancing protein 6 (REEP6), in individuals with autosomal recessive retinitis pigmentosa (RP), the most common form of inherited retinal dystrophy. One individual was molecularly diagnosed with biallelic REEP6 mutations, a missense mutation over a frameshift mutation. In this study, we generated Reep6 compound heterozygous mice, Reep6L135P/-, which mimic the patient genotype and recapitulate the early-onset retinal degeneration phenotypes observed in the individual with RP. To determine the feasibility of rescuing the Reep6 mutant phenotype via gene replacement therapy, we delivered Reep6.1, the mouse retina-specific isoform of REEP6, to photoreceptors of Reep6 mutant mice on postnatal day 20. Evaluation of the therapeutic effects 2 months posttreatment showed improvements in the photoresponse as well as preservation of photoreceptor cells. Importantly, guanylyl cyclase 1 (GC1) expression was also restored to the outer segment after treatment. Furthermore, rAAV8-Reep6.1 single treatment in Reep6 mutant mice 1 year postinjection showed significant improvements in retinal function and morphology, suggesting that the treatment is effective even after a prolonged period. Findings from this study show that gene replacement therapy in the retina with rAAV overexpressing Reep6 is effective, preserving photoreceptor function in Reep6 mutant mice. These findings provide evidence that rAAV8-based gene therapy can prolong survival of photoreceptors in vivo and can be potentially used as a therapeutic modality for treatment of patients with RP.
Collapse
Affiliation(s)
- Smriti Agrawal Zaneveld
- 1 Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX.,2 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Aiden Eblimit
- 1 Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX.,2 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Qingnan Liang
- 1 Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX.,3 Department of Biochemistry, Baylor College of Medicine, Houston, TX
| | - Renae Bertrand
- 1 Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX.,3 Department of Biochemistry, Baylor College of Medicine, Houston, TX
| | - Nathaniel Wu
- 1 Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX.,2 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Hehe Liu
- 1 Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX.,2 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Quynh Nguyen
- 3 Department of Biochemistry, Baylor College of Medicine, Houston, TX
| | - Jacques Zaneveld
- 1 Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX.,2 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Keqing Wang
- 1 Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX.,2 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Yumei Li
- 1 Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX.,2 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Rui Chen
- 1 Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX.,2 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| |
Collapse
|
29
|
Kowalchuk AM, Maurer KA, Shoja-Taheri F, Brown NL. Requirements for Neurogenin2 during mouse postnatal retinal neurogenesis. Dev Biol 2018; 442:220-235. [PMID: 30048641 PMCID: PMC6143394 DOI: 10.1016/j.ydbio.2018.07.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 07/22/2018] [Accepted: 07/23/2018] [Indexed: 02/02/2023]
Abstract
During embryonic retinal development, the bHLH factor Neurog2 regulates the temporal progression of neurogenesis, but no role has been assigned for this gene in the postnatal retina. Using Neurog2 conditional mutants, we found that Neurog2 is necessary for the development of an early, embryonic cohort of rod photoreceptors, but also required by both a subset of cone bipolar subtypes, and rod bipolars. Using transcriptomics, we identified a subset of downregulated genes in P2 Neurog2 mutants, which act during rod differentiation, outer segment morphogenesis or visual processing. We also uncovered defects in neuronal cell culling, which suggests that the rod and bipolar cell phenotypes may arise via more complex mechanisms rather than a simple cell fate shift. However, given an overall phenotypic resemblance between Neurog2 and Blimp1 mutants, we explored the relationship between these two factors. We found that Blimp1 is downregulated between E12-birth in Neurog2 mutants, which probably reflects a dependence on Neurog2 in embryonic progenitor cells. Overall, we conclude that the Neurog2 gene is expressed and active prior to birth, but also exerts an influence on postnatal retinal neuron differentiation.
Collapse
Affiliation(s)
- Angelica M Kowalchuk
- Department of Cell Biology and Human Anatomy, University of California-Davis, Davis, CA 95616, USA
| | - Kate A Maurer
- Division of Developmental Biology, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH 45229, USA
| | - Farnaz Shoja-Taheri
- Department of Cell Biology and Human Anatomy, University of California-Davis, Davis, CA 95616, USA
| | - Nadean L Brown
- Department of Cell Biology and Human Anatomy, University of California-Davis, Davis, CA 95616, USA; Division of Developmental Biology, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH 45229, USA.
| |
Collapse
|
30
|
Cho GY, Schaefer KA, Bassuk AG, Tsang SH, Mahajan VB. CRISPR GENOME SURGERY IN THE RETINA IN LIGHT OF OFF-TARGETING. Retina 2018; 38:1443-1455. [PMID: 29746416 PMCID: PMC6054556 DOI: 10.1097/iae.0000000000002197] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
PURPOSE Recent concerns regarding the clinical utilization of clustered regularly interspaced short palindromic repeats (CRISPR) involve uncertainties about the potential detrimental effects that many arise due to unintended genetic changes, as in off-target mutagenesis, during CRISPR genome surgery. This review gives an overview of off-targeting detection methods and CRISPR's place in the clinical setting, specifically in the field of ophthalmology. RESULTS As CRISPR utilization in the laboratory setting has increased, knowledge regarding CRISPR mechanisms including its off-target effects has also increased. Although a perfect method for achieving 100% specificity is yet to be determined, the past few years have seen many developments in off-targeting detection and in increasing efficacy of CRISPR tools. CONCLUSION The CRISPR system has high potential to be an invaluable therapeutic tool as it has the ability to modify and repair pathogenic retinal lesions. Although it is not yet a perfect system, with further efforts to improve its specificity and efficacy along with careful screening of off-target mutations, CRISPR-mediated genome surgery potential can become maximized and applied to patients.
Collapse
Affiliation(s)
- Galaxy Y. Cho
- Institute of Human Nutrition, Columbia Stem Cell Initiative, College of Physicians and Surgeons, Columbia University, New York, NY, USA
- Jonas Children’s Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, New York, NY, USA
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | - Kellie A. Schaefer
- Omics Lab, Department of Ophthalmology, Byers Eye Institute, Stanford University, Palo Alto, CA, USA
| | | | - Stephen H. Tsang
- Institute of Human Nutrition, Columbia Stem Cell Initiative, College of Physicians and Surgeons, Columbia University, New York, NY, USA
- Jonas Children’s Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, New York, NY, USA
- Department of Ophthalmology, Columbia University, New York, NY, USA
- Department of Cell Biology & Pathology, Columbia University, New York, NY, USA
| | - Vinit B. Mahajan
- Omics Lab, Department of Ophthalmology, Byers Eye Institute, Stanford University, Palo Alto, CA, USA
- Palo Alto Veterans Administration, Palo Alto, CA, USA
| |
Collapse
|
31
|
NMNAT1 E257K variant, associated with Leber Congenital Amaurosis (LCA9), causes a mild retinal degeneration phenotype. Exp Eye Res 2018; 173:32-43. [PMID: 29674119 DOI: 10.1016/j.exer.2018.04.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 03/18/2018] [Accepted: 04/13/2018] [Indexed: 01/25/2023]
Abstract
NMNAT1 (nicotinamide mononucleotide adenylyltransferase 1) encodes a rate-limiting enzyme that catalyzes the biosynthesis of NAD+ and plays a role in neuroprotection. Mutations in NMNAT1 have been identified to cause a recessive, non-syndromic early form of blindness genetically defined as Leber Congenital Amaurosis 9 (LCA9). One of the most common alleles reported so far in NMNAT1 is the c.769G > A (E257K) missense mutation, which occurs in 70% of all LCA9 cases. However, given its relatively high population frequency and the observation of individuals with homozygous E257K variant without phenotype, the pathogenicity of this allele has been questioned. To address this issue, we have studied the pathogenic effects of this allele by generating a knock-in mouse model. Interestingly, no obvious morphological or functional defects are observed in Nmnat1 E257K homozygous mice up to one year old, even after light-damage. Together with the previous clinical reports, we propose that the E257K allele is a weak hypomorphic allele that has significantly reduced penetrance in the homozygous state. In contrast, compound heterozygous Nmnat1E257K/- mice exhibit photoreceptor defects which are exacerbated upon exposure to light. Furthermore, retina tissue- specific Nmnat1 conditional knockout mice exhibit photoreceptor degeneration before the retina has terminally differentiated. These findings suggest that NMNAT1 plays an important role in photoreceptors and is likely involved in both retinal development and maintenance of photoreceptor integrity.
Collapse
|
32
|
Eblimit A, Agrawal SA, Thomas K, Anastassov IA, Abulikemu T, Moayedi Y, Mardon G, Chen R. Conditional loss of Spata7 in photoreceptors causes progressive retinal degeneration in mice. Exp Eye Res 2018; 166:120-130. [PMID: 29100828 PMCID: PMC5756513 DOI: 10.1016/j.exer.2017.10.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 10/10/2017] [Accepted: 10/13/2017] [Indexed: 12/31/2022]
Abstract
The mammalian retina consists of multiple cell layers including photoreceptor cells, which are light sensing neurons that play essential functions in the visual process. Previously, we identified mutations in SPATA7, encoding spermatogenesis associated protein 7, in families with Leber Congenital Amaurosis (LCA) and juvenile Retinitis Pigmentosa (RP), and showed that Spata7 null mice recapitulate the human disease phenotype of retinal degeneration. SPATA7 is expressed in the connecting cilium of photoreceptor (PR) cells in the mouse retina, as well as in retinal pigment epithelium (RPE) cells, but the functional role of Spata7 in the RPE remains unknown. To investigate whether Spata7 is required in PRs, the RPE, or both, we conditionally knocked out Spata7 in photoreceptors and RPE cells using Crx-Cre and Best1-Cre transgenic mouse lines, respectively. In Spata7 photoreceptor-specific conditional (cKO) mice, both rod and cone photoreceptor dysfunction and degeneration is observed, characterized by progressive thinning of the outer nuclear layer and reduced response to light; however, RPE-specific deletion of Spata7 does not impair retinal function or cell survival. Furthermore, our findings show that both Rhodopsin and RPGRIP1 are mislocalized in the Spata7Flox/-; Crx-Cre cKO mice, suggesting that loss of Spata7 in photoreceptors alone can result in altered trafficking of these proteins in the connecting cilium. Together, our findings suggest that loss of Spata7 in photoreceptors alone is sufficient to cause photoreceptor degeneration, but its function in the RPE is not required for photoreceptor survival; therefore, loss of Spata7 in photoreceptors alters both rod and cone function and survival, consistent with the clinical phenotypes observed in LCA and RP patients with mutations in SPATA7.
Collapse
Affiliation(s)
- Aiden Eblimit
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Smriti Akshay Agrawal
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Kandace Thomas
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Ivan Assenov Anastassov
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Tajiguli Abulikemu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030-3411, USA; The Key Laboratory of Plant Resources and Chemistry of Arid Zone, Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi, Xinjiang, 830011, China
| | | | - Graeme Mardon
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030-3411, USA; Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX 77030-3411, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030-3411, USA.
| | - Rui Chen
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030-3411, USA.
| |
Collapse
|